Because of the tremendous expense associated with drilling for oil and gas offshore, oil and gas companies have developed ways to spread the expense associated with manufacturing offshore drilling equipment over a larger number of wells. Typically, in exploring for oil and gas reserves offshore, an exploratory well is drilled with a drill ship or a jack-up rig to determine if the potential oil and gas field is large enough to justify the tremendous expense of manufacturing, assembling, and locating a drilling platform offshore.
If the oil and gas reserves are large enough, a drilling and production platform will be placed over the field. These platforms utilize a movable rig structure that moves back-and-forth along the platform such that multiple wells can be drilled from one platform. After the wells have been drilled, the platform is used to produce oil and gas from these multiple wells.
Over the producing life of the field, it often becomes necessary to perform certain maintenance operations as well as certain stimulation operations aimed at stimulating production from the wells. The drilling rig structure on the platform can be moved over a specific well to perform these servicing operations.
To perform the various operations required of the drilling rig structure, the rig structure must be connected to an electrical power source and a hydraulic fluid supply source. Maintaining connections to these sources, however, has proven difficult in the past with movable drilling rig structures on offshore platforms. Specifically, the prior art “horizontal plane” service arms had a limited range of motion, and, thus, it was difficult to get an extended reach with these horizontal service arms. Often, when using the prior art horizontal service arms, the range of movement of these arms was limited by equipment on the platform and/or drilling rig structure blocking the horizontal service arm from moving in a specific direction. Additionally, preparing the prior art horizontal service arms for transport required disconnecting the electrical and hydraulic supply line connections, thereby increasing the amount of time it takes to prepare the platform for operations once it reaches its offshore destination.
Similarly, prior art “drag chains” suffer from the same limitations as the horizontal service arms. As the name implies, the prior art drag chains are used to drag the supply lines across the platform floor to maintain the connections. Obviously, dragging chains and supply lines across a platform floor that has a significant amount of equipment on it has some limitations. Further, the use of drag chains is a very time consuming process that requires up to a days worth of work to move the supply lines to the drilling rig structures new drilling location. The current invention is designed to alleviate these and other known problems associated with the prior art.
Accordingly, what is needed is a means for maintaining the electrical and hydraulic connections between a junction box or boxes located on or near the platform floor and the drilling rig structure as the drilling rig moves back and forth along the platform. It is, therefore, an object of the present invention to provide a vertically folding service arm capable of moving in both the horizontal and vertical directions in order to provide enhanced range of movement that allows electrical and hydraulic supply lines to remain connected between a junction box located on or near the platform floor and the rig structure even as the rig structure moves back-and-forth on the platform between multiple well centers. It is a further object of the present invention to provide a service arm that can be easily disconnected and “folded” for transport without requiring the electrical and hydraulic supply lines to be disconnected from the drilling rig structure. Those and other objectives will become apparent to those of skill in the art from a review of the specification below.